The Civil Procedure Rules 1998

Affidavit evidence

32.15—(1) Evidence must be given by affidavit(GL) instead of or in addition to a witness statement if this is required by the court, a provision contained in any other rule, a practice direction or any other enactment.

(2) Nothing in these Rules prevents a witness giving evidence by affidavit(GL) at a hearing other than the trial if he chooses to do so in a case where paragraph (1) does not apply, but the party putting forward the affidavit(GL) may not recover the additional cost of making it from any other party unless the court orders otherwise.